• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.3
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• pp.421-435
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• 2017

Recently, due to the saturation of ground structures and the overpopulation of pipeline facilities requires to development of underground structures as an alternative to ground structures. Thus, mechanized tunnel construction of the shield TBM method has been increasing in order to prevent vibration and noise problems in construction of the NATM tunnel for the urban infrastructure construction. Tunnel construction plan for the tunnel line should be formed in a sharp curve to avoid building foundation and underground structures and it is inevitable to develop a shield TBM technology that suits the sharp curve tunnel construction. Therefore, this study is about the structural stability technology of the articulation jack, shield jack and skin plate for the shield TBM thrust in case of the mechanized tunnel construction that is a straight and sharp curve line. The construction case study and shield TBM operation principle are examined and analyzed by the theoretical approach. The torque of the cutter head, the thrust of the articulation jack and the shield jack, the amount of over cutting for curve is important respectively in shield TBM construction of straight and sharp curve line. In addition, it is very important to secure the stability of the skin plate structure to ensure the safety of the inside worker. This study examines the general structure and construction of the equipment, experimental simulation was carried out through numerical analysis to examine the main factors and structural stability of the skin plate structure. The structural stability of the skin plate was evaluated and optimizes the shape by comparing the loads of the articulation jack by selecting the virtual soil to be applied in a straight and sharp curve line construction. Since the present structure and operation method of the shield TBM type in domestic constructions are very similar, this study will help to develop the localized shield TBM technology for the new equipment and the vulnerability and stability review.

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.263-272
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• 2018

The object of this study was to measure the bioactivity and lipid peroxidation inhibition activity of peel from Gardenia jasminoides Ellis fructus (GJE) in Namhae Korea. The amount of phytic acid was also determined. Extraction was performed using three solvents, CM (choloform:methanol, 2:1, v/v), n-butanol and 70% ethanol. To investigate by the solvent extract of total phenol content and value as a functional food ingredient of GJE peel through nitrogen oxide scavenging activity, antioxidant activity, reducing power and lipid peroxidation inhibition were performed. The bioactivities of the extract solvents increased significantly with increasing concentrations (0.2, 0.4, 0.6 mg/mL, p<0.05). The total phenol contents of GJE peel extracts were highest in CM ($39.74{\pm}0.15mg\;CAE/g$) extract. The order of total phenol contents, antioxidant activity and reducing power of the solvents in the GJE peel were the same, in the analysis of nitrogen oxides scavenging activity and lipid peroxidation inhibition, it was confirmed the results were inconsistent. As a result, the GJE peel showed excellent bioactivities. Considering the extraction yield and various physiological activities, it is considered that efficiency is better when extracted from CM and 70% ethanol extracts.

• Geophysics and Geophysical Exploration
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• v.17 no.1
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• pp.1-10
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• 2014

To reveal and classify site characteristics in densely populated areas in Chuncheon, Korea, Rayleigh-waves were recorded at 50 sites including four sites in the forest area using four 1-Hz velocity sensors and 24 4.5-Hz vertical geophones during the period of January 2011 to May 2013. Dispersion curves of the Rayleigh waves obtained by the extended spatial autocorrelation method were inverted to derive shear-wave velocity ($v_s$) models comprising 40 horizontal layers of 1-m thickness. Depths to weathered rocks ($D_b$), shear wave velocities of these basement rocks ($v_s^b$), average velocities of the overburden layer ($\bar{v}_s^s$), and the average velocity to a depth of 30 m ($v_s30$), were then derived from those models. The estimated values of $D_b$, $v_s^b$, $\bar{v}_s^s$, and $v_s30$ for 46 sites at lower altitudes were in the ranges of 5 to 29 m, 404 to 561 m/s, 208 to 375 ms/s, and 226 to 583 m/s, respectively. According to the Korean building code for seismic design, the estimated $v_s30$ indicates that the lower altitude areas in Chuncheon are classified as $S_C$ (very dense soil and soft rock) or $S_D$ (stiff soil). To determine adequate proxies for $v_s30$, we compared the computed values with land cover, lithology, topographic slope, and surface elevation at each of the measurement sites. Due to a weak correlation (r = 0.41) between $v_s30$ and elevation, the best proxy of them, applications of this proxy to Chuncheon of a relatively small area seem to be limited.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.16 no.1
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• pp.24-33
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• 2016

Mucopolysaccharidosis type VI (MPS VI) is a rare disease caused by the mutation of ARSB with prevalence range from 1/5,000 in northeast Brazil to 1/2,057,529 births in Czech Republic. In Asia, there is only one published figure in Taiwan of about 1/833,000 births. The exact prevalence in the Korean population is unknown, but we estimated the incidence of MPS VI is about 0.03/100,000 live births. Enzyme replacement therapy (ERT) with recombinant human Arylsulfatase B (rhASB) is a modality for the treatment of MPS VI that reduces the excretion of urine glycosaminoglycan (GAG) and improves joint motion, pulmonary function, and endurance. We presented the clinical features, molecular analysis and outcome of ERT in three Korean MPS VI patients. All patients had the typical characteristic clinical features of MPS IV. Short stature, dysostosis multiplex, corneal opacity and valvular heart disease were found at first presentation, while restrictive lung disease and carpal tunnel syndrome developed later in all patients. Molecular analysis demonstrated novel missense and nonsense mutation in the patients, including p.Ile 67Ser, p.Gly328Arg, $p.Arg191^*$, p.Asp352Asn, and p.Gly17Asp. After ERT, urine GAG was decreased in all patients. Skeletal involvement, corneal opacity, heart valve abnormalities and pulmonary function were not improved with ERT, but it had a better outcome on regarding joint motion and endurance. One patient underwent allogeneic bone marrow transplantation (BMT) prior to ERT, but their clinical response was not improved much after BMT. This study demonstrates clinical phenotypes and molecular analysis of the severe form of MPS VI in Korean patients.

• Childhood Kidney Diseases
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• v.11 no.1
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• pp.51-58
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• 2007

Purpose : To assess the early complication of laparoscopic peritoneal dialysis catheter implantation in children. Methods : Medical record review was carried out on 21 laparoscopic and 16 conventional peritoneal dialysis catheter implantations which were performed in 31 children under 18 years of age between 2002 and 2006. All medical records were retrospectively analyzed. The patients were followed until 2 months after catheter placement. Patient characteristics and catheterrelated complications, such as significant bleeding, leakage, obstruction, migration, insertion site infection and peritonitis during the first 60 days after implantation were recorded. Results : After conventional operation, dialysate leakage occurred in 2 of 16 cases and all cases improved after conservative management. In 1 case, significant bleeding occurred and re-operation was performed. Three cases of obstruction due to migration were reported, 2 cases underwent reoperation and 1 case improved without intervention. After laparoscopic surgery, outflow obstruction occurred in 1 out of 21 cases, which was caused by adhesion after several reinsertions of the catheter and recurrent peritonitis. No migration was noted after laparoscopic surgery. There was no significant difference in the complication rate between the two groups. Conclusion : Laparoscopic peritoneal dialysis catheter placement is feasible in children of all age groups, with at least equivalent functional results compared to conventional surgery. The additional advantage of laparoscopic catheter insertion is the option to identify and eliminate anatomical risk factors, such as intra-abdominal adhesions, and to perform partial omentectomy without additional incisions.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.138-145
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• 2013

In order to develop the efficient control algorithm of the two-fluid fogging system, cooling experiments for the many different types of fogging cycles were conducted in tomato greenhouses. It showed that the cooling effect was 1.2 to $4.0^{\circ}C$ and the cooling efficiency was 8.2 to 32.9% on average. The cooling efficiency with fogging interval was highest in the case of the fogging cycle of 90 seconds. The cooling efficiency showed a tendency to increase as the fogging time increased and the stopping time decreased. As the spray rate of fog in the two-fluid fogging system increased, there was a tendency for the cooling efficiency to improve. However, as the inside air approaches its saturation level, even though the spray rate of fog increases, it does not lead to further evaporation. Thus, it can be inferred that increasing the spray rate of fog before the inside air reaches the saturation level could make higher the cooling efficiency. As cooling efficiency increases, the saturation deficit of inside air decreased and the difference between absolute humidity of inside and outside air increased. The more fog evaporated, the difference between absolute humidity of inside and outside air tended to increase and as the result, the discharge of vapor due to ventilation occurs more easily, which again lead to an increase in the evaporation rate and ultimately increase in the cooling efficiency. Regression analysis result on the saturation deficit of inside air showed that the fogging time needed to change of saturation deficit of $10g{\cdot}kg^{-1}$ was 120 seconds and stopping time was 60 seconds. But in order to decrease the amplitude of temperature and to increase the cooling efficiency, the fluctuation range of saturation deficit was set to $5g{\cdot}kg^{-1}$ and we decided that the fogging-stopping time of 60-30 seconds was more appropriate. Control types of two-fluid fogging systems were classified as computer control or simple control, and their control algorithms were derived. We recommend that if the two-fluid fogging system is controlled by manipulating only the set point of temperature, humidity, and on-off time, it would be best to set up the on-off time at 60-30 seconds in time control, the lower limit of air temperature at 30 to $32^{\circ}C$ and the upper limit of relative humidity at 85 to 90%.

• Progress in Medical Physics
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• v.21 no.2
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• pp.209-217
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• 2010

Retinal prostheses are being developed to restore vision for the blind with retinal diseases such as retinitis pigmentosa (RP) or age-related macular degeneration (AMD). Since retinal prostheses depend upon electrical stimulation to control neural activity, optimal stimulation parameters for successful encoding of visual information are one of the most important requirements to enable visual perception. Therefore, in this paper, we focused on retinal ganglion cell (RGC) responses to different voltage stimulation parameters and compared threshold charge densities in normal and rd1 mice. For this purpose, we used in vitro preparation for the retina of normal and rd1 mice on micro-electrode arrays. When the neural network of rd1 mouse retinas is stimulated with voltage-controlled pulses, RGCs in degenerated retina also respond to voltage amplitude or voltage duration modulation as well in wild-type RGCs. But the temporal pattern of RGCs response is very different; in wild-type RGCs, single peak within 100 ms appears while in RGCs in degenerated retina multiple peaks (~4 peaks) with ~10 Hz rhythm within 400 ms appear. The thresholds for electrical activation of RGCs are overall more elevated in rd1 mouse retinas compared to wild-type mouse retinas: The thresholds for activation of RGCs in rd1 mouse retinas were on average two times higher ($70.50{\sim}99.87\;{\mu}C/cm^2$ vs. $37.23{\sim}61.65\;{\mu}C/cm^2$) in the experiment of voltage amplitude modulation and five times higher ($120.5{\sim}170.6\;{\mu}C/cm^2$ vs. $22.69{\sim}37.57\;{\mu}C/cm^2$) in the experiment of voltage duration modulation than those in wild-type mouse retinas. This is compatible with the findings from human studies that the currents required for evoking visual percepts in RP patients is much higher than those needed in healthy individuals. These results will be used as a guideline for optimal stimulation parameters for upcoming Korean-type retinal prosthesis.

• Clinical and Experimental Pediatrics
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• v.50 no.10
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• pp.959-964
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• 2007

Purpose : The purpose was to investigate the clinical considerations of patients affected by meconium aspiration syndrome (MAS) and the effect of suctioning through endotracheal intubation immediately after delivery on the prognosis of MAS. Methods : A total of 44 inpatients diagnosed as MAS in the Neonatal Intensive Care Unit (NICU) at Cheil Hospital were selected from January 2004 to June 2006. They were divided into two groups. In the early aspiration group (12 patients), suctioning through endotracheal intubation was performed according to the neonatal resuscitation program of the American Academy of Pediatrics and the American Heart Association because infants born through meconium-stained amniotic fluid (MSAF) were not vigorous after birth. In the early non-aspiration group (32 patients), endotracheal intubation was not performed because the infants born through MSAF were vigorous after birth. These two groups were analyzed retrospectively by medical records in the fields of clinical features, obstetric risk factors, complications, treatment, and duration of hospitalization. Results : There was no significant difference in mean gestational age, mean birth weight, sex, and delivery mode between the early aspiration group and the early non-aspiration group. Mean Apgar score of the early aspiration group both in 1 and 5 minute score was significantly lower than in the early non-aspiration group. Lengths of hospitalization and duration of mechanical ventilator care were longer in the early non-aspiration group, but there was no significant difference. Total duration of oxygen therapy was significantly longer in the early non-aspiration group than in the early aspiration group. Conclusion : In this study, the early non-aspiration group used surfactant more and had a longer duration of mechanical ventilator and hospitalization, but there was no significant difference. Total duration of oxygen therapy was significantly longer in the early non-aspiration group. Therefore, more detailed guidelines for vigorous infants born through MSAF are needed and we should study and follow up the long term prognosis of neurological complications of MAS.

• Childhood Kidney Diseases
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• v.8 no.1
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• pp.33-42
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• 2004

Purpose : Children with nephrotic syndrome(NS) are under high risk for metabolic bone disease(MBD) as a complication of long-term glucocorticoid therapy. We prospectively evaluated the effect of oral bisphosphonate(alendronate) therapy in children with NS, which has proven efficacy in adult patients with glucocorticoid induced MBD. Methods : Among 58 children with NS, aged 5 to 8 years and haying a disease duration of more than 2 years, 30(51.7%) were enrolled to meet the selection criteria, less than -1.0 Z-scores of lumbar spine bone mineral density(BMD) by dual energy X-ray absorptiometry (DEXA). These 30 children were divided into three groups and each were assigned to receive alendronate, calcitriol, and no-medication, respectively for one year. Lumbar spine BMD was followed up every 6 months and the biochemical indexes were measured before and 1 year after the treatment. There were no significant difference among groups with respect to the average age, the initial BMD, and the cumulative steroid doses. Analysis of the treatment efficacy was done by the % change of BMD and by the changes in Z-scores of lumbar spine BMD. Results : Mean age and disease duration of patients at the initial lumbar spine BMD evaluation was $7.4{\pm}1.7$ years and $2.2{\pm}1.2$ years, respectively. Twenty-three of 30 children(76%) had osteopenia, and seven(23%) had osteoporosis. There was no difference in the biochemical values among the groups, before and 1 year after the treatment(P<0.05). Twenty two children(73.3%) with frequent relapsing or steroid dependant NS had more frequent MBD, compared to the 8 children(26.6%) with infrequent relapsing NS. The one year % changes of BMD were 8.56 in alendronate group, 5.79 in calcitriol group, and 1.9 in no-medication group. The changes in Z-score of lumbar spine BMD increased in the alendronate group and the calcitriol group, but not in the no-medication group. One year % changes of BMD were different among groups(P=0.0002). Significant differences were found between the alendronate and the no-medication group, and between the calcitriol and the no-medication group(P<0.05). There was no difference between the alendronate and the calcitriol group. No serious adverse effect was observed in the alendronate group. Conclusion : Children with NS receiving high dose steroids are under the high risk of BMD and should undergo regular BMD evaluation. Z-score of lumbar spine BMD was a useful parameter in diagnosing low bone mass in children. Alendronate weekly oral therapy was effective and relatively safe in increasing the lumbar spine BMD in children with NS having steroid induced MBD.

• Childhood Kidney Diseases
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• v.12 no.2
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• pp.213-220
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• 2008

Purpose : This study aims to verify the effectiveness of initial empirical antibiotic choice recommended by the International Society for Peritoneal Dialysis(ISPD) guide among Korean children. Methods : We have collected data on peritonitis from January 2001 to December 2007 in Samsung Medical Center. Results : Of the 42 patients, 48 episodes of peritonitis had occurred in 21 patients. The rate of peritonitis was one episode over 35.3 patient-months. Mean dialysis duration before peritonitis was 18.06$\pm$15.81 months. Gram-positive organisms accounted for 58.3% of all episodes. Of the gram-positive organisms, the most common pathogen was Staphylococcus aureus(29.2%), the next common pathogens were Coagulase negative staphylococcus(14.6%) and Streptococcus species(6.3%). 35.7% of gram-positive pathogens were resistant to 1st cephalosporin. However, in patients younger than 4 years old, 50% of gram-positive pathogens were resistant to 1st generation cephalosporin. 10 episodes of peritonitis were methicillin-resistant and were treated by vancomycin. Of the gram-negative organisms, E. coli was the most common (8.3%). 64.8% of all pathogens were sensitive to cephalothin or ceftazidime. Conclusion : The empirical therapy with 1st generation cephalosporin and ceftazidime can be also effective to peritoneal dialysis associated peritonitis in Korean children. However, in patients younger than 4 years old, glycopeptide should be considered as the first empirical therapy in Korean children.